The invention relates to a display device for illustrating color mixtures, in which various transparent color wheels, each having one color printed on it in various intensities, are disposed concentrically with one another and individually rotatably and are each provided along their circumference with a tab for adjustment.
A display device of this kind is known from German Pat. No. 568 995. According to the exemplary embodiment of FIGS. 1-4 of this publication, it is known to displace a plurality of color wheels, printed in various colors, relative to one another in such a way that various mixtures of the colors are produced. Each of these color wheels is embodied such that it is printed with a certain color, but in various intensities. The various intensities produce a certain pattern on each color wheel. However, these patterns are different from one color wheel to another. When the wheels are displaced, there is no systematic contribution made by the individual color ingredients, dependent for instance on the extent of displacement, in the color mixture attained. The appearance of various color mixtures as the color wheels are displaced relative to one another instead appears to occur relatively arbitrarily in succession with one another. Thus with this device it is not possible to rapidly and systematically display a color mixture that can be associated with predetermined percentages (per cent with respect to the color intensity) of the individual colors used for the mixture. Conversely, it is also not possible with a predetermined color mixture to discover with which degree of intensity (from 0 to 100%) the individual color components have contributed to this mixture. Furthermore, because of the spatial disposition of a predetermined point having a predetermined color mixture inside all of the panels, it would be difficult to compare a color mixture just being produced at a predetermined point inside the color wheel with a predetermined color, for instance on a printed piece of advertising material. The exemplary embodiment of FIG. 5 of this publication now shows that such color wheels can be glued in in the form of circular-segmental sections of circular panels, so that the displacement of the color wheels relative to one another is done by rotation of the concentric panels relative to one another, which for rotation are also provided with tabs that protrude on the outer rim. Here again, however, the disadvantage is still that the dispositions of the regions of various color intensity on each color wheel is not systematic, so that from the rotational position of the individual color wheels no conclusion can be drawn as to which color intensity of each of the colors used of the individual color wheels has participated in a color mixture. Furthermore, a color mixture occurs at a predetermined point inside the circular segment, and it is extraordinarily difficult then to compare this point precisely with a point on a printed document or the like.
In U.S. Pat. No. 2,522,723, a plurality of color wheels are disposed, each being rotatable about different axes of rotation, in a box-like housing. The circumferential surface is divided into circular segments, and each wheel is printed each with one color in gradations from one circular segment to another with decreasing or increasing intensity of the colors. At one point, the outer edges of all four wheels overlap. At a predetermined rotational position, a predetermined color mixture is then produced; thus from the rotational position of the wheels it is apparent which intensity of each of the color wheels used is a component in the resultant color mixture. However, this device is not suitable for a desired comparison of the color mixture produced with a colored portion of advertising or some printed product, for ascertaining the same color mixture or one that matches it, because the device has a very tall structure; this is also necessary, because a special stamping mechanism is provided so that after adjustment, the color wheels resting one over the other at the special point mentioned can be pressed against an observation-proof window. Furthermore, in the preparation of color mixtures it is disadvantageous that to this end the individual color wheels have to be printed with the individual colors in different intensity in very complicated patterns, so that when they overlap the individual grid points will coincide exactly. In the arrangement according to U.S. Pat. No. 2,522,723, color interferences would be produced if the device were used in halftone printing. Finally, another disadvantage of this arrangement is that the point at which the color mixture is produced is located in the center; that is, it cannot be displaced on a printed document in such a way that the color mixture arrived at can be placed directly next to a particular already-existing color for comparison purposes.